Michael  s



(No Model.)

M. s. WELLER. DEVICE FOR OVERGOMING DEAD CENTERS. No. 249,492. Patented Nov. 15,1881.

.dttomey x. Lrlhograplwn Wishingicn. u c.

UNITED STATES PATENT I OFFICE.

MIGHAEL 'S. WELLER, OF OHARLESTOVVN, WEST VIRGINIA, ASSIGNOR TO HIMSELF AND THOMAS W. DAVIS, OF SAME PLACE. I

SPECIFICATION forming part of Letters Patent No. 249,492, dated November 11 5, 1881.

Application filed October 7, 1881. (No model.)

To all whom it may concern Be it known that I, MICHAEL Soo'r'r WEL- LER, of Oharlestown, in the county of Jeft'erson and State of West Virginia, a citizen of the United States,have invented an Improved Device for Overcoming the Dead-0enters of Cranks, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, making partof this specification, in which- Fi'gure l is an elevation of a driving-wheel operated by a treadle, the connecting-rod or pi-tman being secured to the former by means of my improved device. Fig. 2 is a perspective view of my device detached, a portion of one side being broken away to show the interior. Fig.3 isa longitudinal section through the center of the same.

.My present invention consists in a yielding connection or wrist between the pitman and the driving-wheel, to be hereinafter described and specifically claimed.

In thesaid drawings, Arepresents the treadle of a sewing or other light machine, to which i the lower end of a pitman, B, is pivoted at a, the upper end of the latter being secured to the driving-wheel O by means of an adjustable wrist or crank pin, D, of the following construction:

E is a rectangular box, secured by one or more screws, 1), to the arm 0 of the wheel (3 at an angle of about'forty-five degrees (45 with its longitudinal center. This box is provided with a lid or cover, d, having ail enlargement, 6, extending down from its center, and a spiral spring, f, located at each end thereof, the tension of the springs being regulated by screws h, bearin g against bent plates i. Passing into this central enlargement, e, from its outside is thread on its inner end and a large head on its outer end. This pin D, I term a wrist or crank? pin, and the box secured to the arm 0, I designate a wrist-box, E. The pitman is allowed to pass over its critical points or dead-centers by prcssin g the central enlargement or block, 0, with its wrist against the sprin g f, on the side opposite that in. which the pitman is moving, each side of the central block, 6, being provided with a slot, 70, (see Fig. 2,) into which projects a screw, Z, to limit its throw in that direction.

It will be seenfrom the foregoing that my invention may bcapplied to sewing-machines, lathes, drills, saws, and other light mechanism driven by foot-power, the pressure on the treadle at any position of the pitman being always sufficient to start the driving-wheel.

It is also evident that my improvement may be used to advantage on many other classes of mechanism operated by foot or other power.

, I claim- 1. A yielding wristor crank pin, ID, for connecting the pitman B with the driving-wheel G, constructed and arranged to operate substantially as and for the purpose described.

2. The wrist-box E, secured to the face or an arm of the wheel 0, in combination with the sliding lid or cover d, having a slotted en largement or block, 6, located between a pair of springs, f, and with the Wrist-pin D projecting therefrom, substantially as set forth.

Witness my hand this 5th day of October, 881.

MICHAEL SCOTT WELLER. In presence of- T. W. MITCHELL, D. A. PHILLIPS. 

